Add a second label to an inherited node in spring-data-neo4j-4

Question

Let's have this class structure:

@NodeEntity
abstract class BasicNodeEntity {
    @GraphId
    private Long nodeId;
    //...
}

abstract class IdentifiableEntity extends BasicNodeEntity {
    private String id;
    //...
}

abstract class Ad extends IdentifiableEntity {
    //... Ad attibutes
}

class OfferAd extends Ad {
    // ... OfferAd attibutes
}

Saving an OfferAd node through a Neo4jRepository, I expect the node would have two labels: OfferAd and Ad (inherited). However, the label Ad is not added to the node.

I know I can do it saving the node through a cypher query, but I'm wondering if it's posible through a Neo4jRepository instead.

I've reviewed this question (related to SDN3) and I think it's very close to my use case, but it seems to be not working...

Any help would be appreciated. Thanks

score 9 · Accepted Answer · answered Aug 28 '16 at 08:06

The rules for labels are as follows:

any plain concrete class in the hierarchy generates a label by default
plain abstract class does not generate a label by default
plain interface does not generate a label by default
any class annotated with @NodeEntity or @NodeEntity(label="something") generates a label
empty or null labels must not be allowed
classes / hierarchies that are not to be persisted must be annotated with @Transient

Therefore if you remove abstract from your base class, or add a @NodeEntity annotation, you should see the results you expect.

Additionally (new in OGM 2.0.4 and fixes in 2.0.5), you can add and remove additional labels by creating a field of type Collection<String> and annotating it with @Labels, for example:

@Labels
private List<String> labels = new ArrayList<>();

To use version 2.0.4 (gradle):

compile "org.neo4j:neo4j-ogm-core:{version}"
compile "org.neo4j:neo4j-ogm-http-driver:{version}"

You're welcome @troig :) Let us know if you have any issues getting 2.0.4/5 integrated. — Jasper Blues, Aug 28 '16 at 08:58

score 2 · Answer 2 · answered Aug 27 '16 at 10:10

As simple as adding the @NodeEntity annotation to the Ad class as well. It seems to be that spring-data-neo4j-4 only creates one label per node by default, even if the node inherites another one.

If we want to allow SDN to add the parent label classes as well, we need to add @NodeEntity to them.

So, for this use case, if we add it to Ad class,

@NodeEntity
abstract class Ad extends IdentifiableEntity {
   //... Ad attibutes
}

when we save an OfferAd through a Neo4jRepository, the node created will have both labels: Ad and OfferAd.

Add a second label to an inherited node in spring-data-neo4j-4

2 Answers2